16MHz Crystal Oscillator, HC49/US Package

A microcontroller's internal clock source often isn't precise or stable enough for applications needing exact timing (reliable serial communication baud rates, USB timing, precise delay calculations) - an external crystal oscillator like this 16MHz unit provides that precision reference, oscillating at a tightly controlled frequency that a microcontroller's clock circuitry locks onto for considerably more accurate and stable timing than its internal RC oscillator alone.

16MHz is one of the most commonly used crystal frequencies in hobby electronics specifically because it's the frequency classic Arduino boards (and the ATmega328P chip at their core) are built around, making this crystal a direct replacement or spare for that exact application, or a general-purpose 16MHz reference for any other microcontroller design built around that frequency.

Frequency tolerance is rated at 30 parts-per-million, a standard tolerance for this crystal class, adequate for the vast majority of hobby and general digital timing applications that don't require laboratory-grade frequency precision. The HC49/US package is a compact surface-mount form factor, and operating temperature spans -10 to 60C, suiting typical indoor electronics use.

Builders repairing or building a custom Arduino-compatible board, designing a microcontroller circuit needing a precise 16MHz timing reference, or needing a spare crystal for an existing 16MHz-based design will find this crystal oscillator a direct, standard component for that specific timing need.